First of all, you need a Jailbroken device.
Then you need iFile (get it from the Cydia store).
In iFile you go to: var/mobile/applications/fifa12app/ini/na/career.ini -->
open with textviewer.
Change this:
FORCE_QUICKSIM_OUTCOME = 1 instead of 0 (now you'll always win the quick simulation)
Scroll down until you find:
TICKET SALE MULTIPLIER = 1000000 (add a huge number )
TICKET SALES POWER = ADD 1000
TICKET SALE RAISER = ADD 1000000
(scroll down again)
INITIAL MONEY TWEAKER = 1000000000000000 (also a huge number)
Note: I tried it myself and found out that you have to start a new career to get more money.
I did so and got 1.434.164.999 instead of 5.000.000 €.
I don't know if you get more money from each match. You have to try it yourself or I will post it later when I find it out.
(sorry for my bad english, I'm from germany)
I hope this helps you .
€: I tried something and I think it worked (if you want more money - works for old careers too):
I changed MONEY_PLUS_SMALL =
MONEY_PLUS_MED =
and MONEY_PLUS_LARGE =
and added a huge numbers.
Now I get more than 2.000.000.000 on every home match.
I'll tell you when I find out more .